JP2007022280A - Peripheral monitoring device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a peripheral monitoring device for a vehicle capable of appropriately obtaining necessary output signal from a radar device under various conditions without driver's being aware of it while using the radar device for both parking support and rear-end collision detection. <P>SOLUTION: The peripheral monitoring device for the vehicle is equipped with a radar device having a transmission means 1 transmitting a detection radio wave toward vehicle outside, a receiving means 2 receiving a reflection radio wave from an external object, and a signal processing means 3 detecting the external object based on the detection radio wave and the reflection radio wave, and a mode setting means 5 switching and setting to either operation mode of the parking support mode operating the radar device 4 as a support monitor in parking marshalling or a rear-end collision detection mode operating the radar device as a rear-end collision detection monitor in traveling marshalling. The mode setting means 5 sets the radar device to either the parking support mode or the rear-end collision detection mode based on the vehicle state data based on a driving attitude data and a vehicle speed data or the like. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle periphery monitoring device provided with radar means for detecting an external object based on a reflected wave of a detection wave transmitted toward the outside of the vehicle.

Various proposals have been made for a vehicle periphery monitoring device equipped with radar means for detecting obstacles existing around the vehicle using reflection of electromagnetic waves. For example, in a peripheral monitoring device provided with radar means for rear monitoring, in order to effectively use the monitoring device in both forward and reverse traveling states, a transmission means for transmitting a laser detection wave toward the outside of the vehicle, and an external object Receiving means for receiving the detection wave reflected by the motor, peripheral monitoring means for controlling the transmitting means and the receiving means and detecting an external object based on the received wave, and a shift for detecting the shift position of the transmission of the vehicle drive system A vehicle periphery monitoring device has been proposed that includes position detection means and area change means that is provided in the periphery monitoring means and changes a detection area for detecting an external object in accordance with the shift position.
JP-A-10-186032

  The above-described conventional vehicle periphery monitoring device uses a single radar means for detecting an approaching vehicle from the rear when the vehicle is moving forward, and for detecting an obstacle when moving backward for parking. Although it is configured with area changing means that changes the detection area for detecting external objects according to the shift position of the machine, the detection area of the radar means is close when the shift position is simply operated to the reverse position Because it was changed to the area, if the shift position is operated to the forward position by turning back when parking the vehicle, the detection area is switched to the far area and an appropriate output signal for parking support can not be obtained. Appropriate information was not always available. For this reason, it is necessary to provide a proximity mode forcible switch for fixing the detection area of the radar means to the proximity area and to perform the fixing operation in the proximity mode during parking operation.

  On the other hand, if the detection area of the radar means is fixed in the proximity area during parking operation, another vehicle approaching from behind cannot be detected.

  In view of the above-described conventional problems, an object of the present invention is to appropriately output a necessary output signal from a radar unit under various circumstances without the driver being conscious while using the radar unit for parking assistance and rear-end collision detection. The present invention provides a vehicle periphery monitoring device that can be obtained.

  In order to achieve the above object, a first characteristic configuration of a vehicle periphery monitoring device according to the present invention is a vehicle including radar means for detecting an external object based on a reflected wave of a detection wave transmitted toward the outside of the vehicle. Mode setting for switching the operation of the radar means to one of a parking assistance mode for operating as a support monitor during parking operation and a rear-end collision detection mode for operating as a rear-end collision detection monitor during traveling vehicle operation. Means for setting the radar means to either the parking assistance mode or the rear-end collision detection mode based on the vehicle state data.

  Although it is possible to entrust the driver's intention to set the operation mode of the radar means to the parking assistance mode or the rear-end collision detection mode, there are cases where the selection is not always appropriate. For example, it is necessary to consider when the driver makes a setting error or neglects the setting. Even in such a case, if the operation mode is set based on the vehicle state data, it is possible to prevent the occurrence of a situation where at least a meaningless operation mode is set. . Here, the vehicle state data is a single data or a plurality of data that can determine whether the vehicle is at least a parking maneuver or a traveling maneuver.

  The second feature configuration is that, in addition to the first feature configuration described above, the vehicle state data is driving posture data detected by posture detecting means for detecting the driving posture of the driver.

  The driving posture is remarkably different between when the driver performs parking and driving. For example, when driving a vehicle, a seat belt is attached and the seat is stably seated and a certain amount of weight is applied to the backrest. Changes and the position of the center of gravity applied to the seat changes as it moves away from the backrest. By detecting such a state using any sensor, it is possible to appropriately determine whether to set the parking assistance mode or the rear-end collision detection mode.

  The third characteristic configuration is that, in addition to the first characteristic configuration described above, the vehicle state data is vehicle speed data detected by a vehicle speed sensor and shift position data detected by a shift position detecting means.

  When the vehicle is parked, the vehicle speed is low and the shift position is set to the reverse position or the drive position, whereas when the vehicle is driven, the shift position is set to a drive position at a certain high speed. Therefore, by determining the vehicle operating state based on the vehicle speed data and the shift position data, it is possible to appropriately determine whether to set the parking assist mode or the rear-end collision detection mode.

  The fourth characteristic configuration is that, in addition to the first characteristic configuration described above, the vehicle state data is steering angle data detected by a steering angle sensor.

  When the vehicle is parked, the steering operation is greatly performed, whereas when the vehicle is driven, the steering operation is not so large. Therefore, by detecting the degree of the steering operation by the rudder angle sensor, it is possible to appropriately determine whether to set the parking assist mode or the rear-end collision detection mode.

  In the fifth feature configuration, in addition to any of the first to fourth feature configurations described above, the radar means is a CW radar or an FMCW radar, and the signal processing means depends on a set operation mode. And a band switching means for switching a band for performing frequency analysis.

  When using CW radar or FMCW radar as the radar means, the acceleration level of the external object to be detected is greatly different between the parking assistance mode and the rear-end collision detection mode. When the approach speed of an external object is detected based on the Doppler frequency by the signal processing means, usually a narrow band comb filter or a fast Fourier transform is usually used to improve measurement accuracy. By making the target frequency band different between the parking assistance mode and the rear-end collision detection mode, unnecessary signal processing can be omitted, and detection processing can be performed at high speed.

  In the sixth feature configuration, in addition to any one of the first to fourth feature configurations described above, the radar means is a spread spectrum radar, and a sliding correlation with an external object according to a set operation mode. A correlation calculation switching means for switching the calculation is provided.

  The relative distance between the external object to be detected and the vehicle is greatly different between the parking assistance mode and the rear-end collision detection mode. Therefore, when a spread spectrum radar is used as the radar means, detection processing can be performed at high speed by switching the sliding correlation calculation so as to perform only the correlation calculation of a necessary distance.

  In the seventh feature configuration, in addition to any one of the first to fourth feature configurations described above, the radar unit includes an area switching unit that switches a detection area for an external object in accordance with a set operation mode. There is in point.

  In the parking assistance mode and the rear-end collision detection mode, the relative distance and the detection angle between the external object to be detected and the vehicle are greatly different. Therefore, the target object can be efficiently detected by switching the tracking range for the external object by the area switching means.

  The eighth feature configuration is temporarily switched to the other operation mode during any one of the operation modes set by the mode setting means in addition to any of the first to seventh feature configurations described above. Priority mode setting means for preferentially setting the operation mode based on the output signal from the radar means at that time is provided.

  According to the above-described configuration, the operation mode is appropriately set by the priority mode setting unit regardless of whether the radar unit is operating in the parking support mode or the rear-end collision detection mode set by the mode setting unit. Will be able to change. For example, the priority mode setting means temporarily changes the setting to the rear-end collision detection mode when the radar means is set to the parking assist mode, and preferentially maintains the rear-end collision detection mode when a vehicle approaching from the rear is detected. If not, it is set to return to the parking assist mode. As described above, even when one of the operation modes is set, the other operation mode is temporarily set and priority is given to one of the operation modes based on the state of the detected external object. It becomes possible to perform.

  As described above, according to the present invention, a vehicle that can appropriately acquire a necessary output signal from the radar means under various circumstances without using the radar means, while the radar means is used for parking assistance and rear-end collision detection. It became possible to provide a peripheral monitoring device.

  A vehicle periphery monitoring device according to the present invention will be described below. As shown in FIG. 1, the vehicle periphery monitoring device includes a radar unit 4 that detects an external object based on a reflected wave of a detection wave transmitted toward the outside of the vehicle, that is, a transmission unit 1 that transmits a detection radio wave, A receiving means 2 for receiving a reflected radio wave from an external object, a signal processing means 3 for detecting an external object based on the detected radio wave and the reflected radio wave, and a radar means 4 for detecting an external object located behind the vehicle; Mode setting for switching and setting based on vehicle state data between one of a parking support mode in which the radar unit 4 is operated as a support monitor at the time of parking and a rear-end collision detection mode in which the radar unit 4 is operated as a rear-end collision detection monitor at the time of traveling Means 5, a parking support means 10 that operates in the parking support mode, and a rear-end collision detection means 20 that operates in the rear-end collision detection mode. The radar unit 4, the mode setting unit 5, the parking support unit 10, and the rear-end collision detection unit 20 are each configured with a microcomputer and peripheral hardware that perform arithmetic processing based on a predetermined control program. In this way, desired control is executed while data is transmitted to and received from a plurality of other control units (ECUs).

  The radar means 4 is a radar that employs a spread spectrum system, and the transmitting means 1 is a PN code generating means 1d for generating a predetermined pseudo noise (PN) code, and a carrier signal from the carrier signal generating means 1a is PN A modulation unit 1b that performs spread spectrum modulation using a PN code signal generated by the code generation unit 1d, a transmission antenna 1c that transmits a modulated carrier as a radar radio wave, and the like are configured. The reception unit 2 includes the radar radio wave In order to remove the receiving antenna 2c that receives the radar radio wave reflected and returned by an obstacle or the like that is an external object located in the transmitting direction, and the carrier signal component included in the received signal output from the receiving antenna 2c, Based on the output signal from the carrier signal generating means 2a that generates a signal equivalent to the carrier signal It is configured to include a demodulation means 2b etc. for spread spectrum demodulation. The shape of the transmitting antenna 1c and the receiving antenna 2c is not limited as long as the above-described radar signal can be transmitted and received. In the present invention, the transmitting antenna 1c and the receiving antenna 2c are shared for transmission and reception, but are provided separately. Also good.

  The signal processing means 3 obtains a correlation processing means 3a for mixing and outputting the delayed PN code generated by the PN code generation means 1d and the received signal, and a correlation output in the mixing output from the synchronization processing means 3a. A correlation calculation means 3c for outputting a distance signal corresponding to the distance to each of the plurality of objects reflecting the radar radio wave based on the correlation output, and a relative velocity signal of the external object based on the correlation output of the correlation calculation means 3c. And a Doppler computing means 3b for computing the relative speed and distance change rate of each external object.

  In the synchronization processing unit 3a, each of the PN signals delayed by the plurality of variable delay processing units and the received signal are mixed by a plurality of multiplication processing units, and the correlation calculation unit 3c performs a plurality of corresponding processing based on the mixing output. The correlation output is calculated by the correlation processing unit.

Specifically, as shown in FIG. 2, the PN code S _PN (t) transmitted from the transmitting antenna 1c and the radar radio wave including the PN code are reflected by an external object and returned to the received signal after τ seconds. The included PN code S _PN (t−τ) is multiplied by the multiplication processing unit, and a mixing signal S _PN (t−τ) · S _PN (t), which is the product of these, is output. In the correlation processing unit, a correlation output signal is calculated and derived by time-integrating the calculated mixing signal, and the correlation output signal is fed back to the variable delay processing unit of the synchronization processing means 3a. In the variable delay processing unit, the phase delay amount is feedback-controlled so that the correlation output signal is maximized.

The phase difference between the transmitted PN code and the received PN code at the time when the correlation output signal becomes maximum coincides with the received PN code, and the distance to the object is derived. That is, the distance L to the external object is obtained based on the following equation by obtaining the delay time t corresponding to the phase delay amount in the variable delay processing unit at the time when the above correlation output signal becomes maximum. . Such a series of calculation processing is called sliding correlation calculation. In order to detect a plurality of external objects existing from a short distance to a long distance corresponding to the range of the reflection time τ, a plurality of variable delay processing units, multiplications are performed. A processing unit, a correlation processing unit, and the like are provided.
L = (t · c) / 2
Where c: speed of light (3 × 10 ⁸ m / sec)
The Doppler calculation means 3b calculates a Doppler frequency fd that depends on the relative movement speed of the external object based on the input correlation output signal, calculates a relative speed signal corresponding to the value, and derives the following equation: Based on the above, the relative speed Δv and the distance change rate ΔL per predetermined time tu are calculated and derived.
Δv = fd × (c / fpn)
ΔL = Δv × tu
Here, fpn: PN frequency Since the correlation output signal is output every one period of the PN code of the received signal, the period (correlation period) Tcs of the correlation output signal is a Doppler effect due to the movement of an external object or its movement It becomes the same value as one period of the PN code in which the Doppler shift is received in response to the change in distance due to. Therefore, the Doppler frequency fd is calculated and derived by the following formula based on the correlation period of the correlation signal output.
fd = (1 / Tcs ₁ ) − (1 / Tcs ₂ )
Here, Tcs ₁ : Time from the peak of the correlation output signal by the first PN code to the peak of the correlation output signal by the next code Tcs ₂ : From the peak of the correlation output signal by the second PN code to the last PN code The time until the peak of the correlation output signal by the parking assist means 10 is used to operate the vehicle at an appropriate parking position without touching an external object that is an obstacle such as a structure or another vehicle when the vehicle is parked. A device that assists driving through guidance and monitor display, and is based on the position of an external object at a short distance detected by the radar unit 4 and the vehicle body data and steering performance data stored in the storage unit in advance. Parking assistance display processing means for generating display information of relative relationship with the vehicle position, and parking assistance voice output means for guiding and outputting an appropriate steering operation When the mode setting unit 5 switches from the rear-end collision detection mode to the parking support mode, the relative display information by the parking support display processing unit described above is switched to the touch panel type monitor 9 shared with the navigation device 30 and the like. In addition to the display, the output signal from the parking assist voice output means is switched and output to the speaker 8 shared with the navigation device 30 and the audio system (not shown).

  The rear-end collision detection means 20 calculates the relative position and relative speed with respect to the host vehicle based on the position and speed of the rear vehicle that is an external object detected by the radar means 4, and there is a risk of collision. A rear-end collision detection display processing means for generating display information of relative relationship with the own vehicle position and a rear-end collision detection voice output means for guiding and outputting an appropriate driving operation are provided. When switching to the detection mode, the relative display information by the above-described collision detection display processing means is switched and displayed on the monitor 9, and the output signal from the collision detection sound output means is switched and output to the speaker 8. Further, the rear-end collision detection means 20 includes an active headrest control means for controlling an actuator incorporated in the headrest 7 based on an output signal from the rear-end collision detection means 20 to alleviate the impact applied to the occupant during the collision. .

  The mode setting means 5 is a setting mode in which the set mode, that is, the parking support mode or the rear-end collision detection mode is displayed on the monitor 9 and the mode switched through the speaker 8 is voice-guided. Guiding means is provided, and the current mode is configured to be confirmed by the driver.

  The switching setting of the operation mode to either the parking support mode or the rear-end collision detection mode by the mode setting unit 5 described above is based on the vehicle state data detected by the vehicle information detection unit 6. The vehicle information detection means 6 includes an attitude detection means 6a for detecting the driving attitude of the driver, a vehicle speed detection means 6b for detecting the traveling speed of the vehicle, a shift position detection means 6c for detecting the operation position of the shift gear, and a steering. A steering angle detection means 6d for detecting the operation angle is provided.

  The posture detection means 6a is an imaging device provided with a seat belt attachment / detachment detection sensor, a physique detection sensor composed of a plurality of load sensors attached to the driving seat, and an image processing means for analyzing the driving posture of the driver from the photographed image. Any of the means, or a combination thereof, for example, when the seat belt is attached, the vehicle is in a traveling vehicle operation state, and when the seat belt is detached, the vehicle is in a parking vehicle operation state. When the driver's center of gravity position detected by the sensor is behind the seat or when a load is applied to the backrest, the vehicle is in a driving state, and the driver's center of gravity position is in front of the seat or the load on the backrest is reduced. Sometimes it is detected that the vehicle is in the parking maneuvering state, and it is detected by the image processing means that the driver is in a stable posture facing forward. Is in the running maneuvering state to come, the attitude that is staring at the attitude and the rearview mirror or the left and right side mirror that look back at the rear is detected to be in the parking maneuvering state when it is detected.

  The vehicle speed detecting means 6b detects that the vehicle is in a traveling vehicle operation state when the vehicle speed is higher than a predetermined low speed, and is in a parking vehicle operation state when the vehicle speed is lower than the predetermined low speed.

  The shift position detecting means 6c detects that the vehicle is in the traveling vehicle operation state when the shift position is the forward position and the high speed traveling gear is selected, and that the vehicle is in the parking vehicle operation state when it is in the reverse position.

  The steering angle detection means 6d is in a parking vehicle operating state when the steering angle is operated to be larger than a predetermined angle, and is in a traveling vehicle operating state when being operated in a range smaller than the predetermined angle. To detect.

  The mode setting means 5 is determined to be in a traveling vehicle operating state based on vehicle state data based on any one or combination of the above-described attitude detection means 6a, vehicle speed detection means 6b, shift position detection means 6c, and steering angle detection means 6d. The rear-end collision detection mode is switched to the parking assist mode when it is determined that the vehicle is in the parking operation state.

  Specifically, when the vehicle speed detection unit 6b and the steering angle detection unit 6d or the shift position detection unit 6c detect that the vehicle is in a parked vehicle operating state, the posture detection unit 6a and the vehicle speed detection It is preferable to switch to the parking assistance mode when the means 6b or the shift position detection means 6c detects that the vehicle is in the parking operation state, and to set the rear-end collision detection mode in other cases. As described above, the operation mode is automatically set by the mode setting means 5 based on the vehicle state data. If the operation mode of the vehicle periphery monitoring device is only set manually by the driver, This is because it may be difficult to set an appropriate operation mode sometimes, or it may not be possible to properly monitor due to an incorrect setting, so that a more appropriate state can be set.

  Further, the mode setting means 5 described above includes manual mode setting means 5b for switching to any mode by manual operation regardless of the automatic setting of the operation mode based on the vehicle state data detected by the vehicle information detection means 6 described above. Priority mode setting for temporarily switching to the other operation mode during one of the operation modes by automatic setting or manual setting and preferentially setting the operation mode based on the output signal from the signal processing means 3 at that time Means 5a are provided.

  The mode set by the mode setting means 5 is displayed on the monitor 9, and the display mode is configured to display either the rear-end collision detection mode or the parking assistance mode, The manual mode setting means 5b switches to the parking support mode when the key is pressed while the rear-end collision detection mode is displayed, and the rear-end collision detection mode when the key is pressed while the parking support mode is displayed. Operates to switch to Therefore, the operation mode can be appropriately switched even when the mode is set against the driver's intention. In addition, it is configured to switch to the automatic setting mode when the key is pressed again in the state where the operation mode is switched by manual operation, but the display area displays whether the mode is set to manual or automatic. By doing so, it is possible to configure so that the driver can grasp.

  The priority mode setting means 5a is a mode for switching the operation mode at a constant interval of several seconds to several tens of seconds and confirming the state of the external object behind the vehicle, and is set to the parking assist mode in the automatic mode or the manual mode. Sometimes it temporarily switches to the rear-end collision detection mode to detect the state of the rear vehicle, and when it is judged that there is no risk of rear-end collision based on the detected distance and speed or acceleration, the parking assist mode is continued as it is and the rear-end collision is continued. The priority is set to the rear-end collision detection mode when it is determined that there is a risk of the rear-end collision. When it is determined that there is no danger of collision based on the detected distance and speed, the rear-end collision detection mode is continued and the collision is continued. It is intended to preferentially set the parking support mode when it is determined that there is a risk.

  As described later, the priority mode setting means 5a is provided in such a manner that the operation of the radar means 4 is different between the parking support mode and the rear-end collision detection mode. This is because an obstacle behind a short distance cannot be sufficiently detected in the rear-end collision detection mode, and when the operation mode is temporarily switched by the priority mode setting means 5a, the rear-end collision is performed only by switching the operation mode of the radar means 4. The operation of the detection unit 20 or the parking support unit 10 is maintained.

Hereinafter, the configuration of the radar means 4 corresponding to the above-described operation mode will be described in detail. As described above, a plurality of variable delay processing units, multiplication processing units, correlation processing units, etc. are provided corresponding to the range of the reflection time τ for sliding correlation calculation. It is not necessary to detect the following vehicle, and it is not necessary to detect nearby obstacles in the rear-end collision detection mode. Therefore, only a variable delay processing unit, a multiplication processing unit, a correlation processing unit, etc. corresponding to an external object that needs to be detected among a plurality of variable delay processing units, multiplication processing units, correlation processing units, etc. are selectively selected according to the operation mode. Correlation calculation switching means 3d to be operated is provided to reduce calculation load and realize high-speed processing. Selection of a variable delay processing unit, a multiplication processing unit, a correlation processing unit, and the like that are activated according to the operation mode is determined based on a predetermined reference reflection time τ _th , and in the parking support mode, a reflection shorter than the reference reflection time τ _th Each processing unit corresponding to the time τ is selected corresponding to the reflection time τ longer than the reference reflection time τ _{th in the} rear-end collision detection mode.

  Furthermore, the transmitting antenna 1c and the receiving antenna 2c constituting the transmitting means 1 are array antennas in which a plurality of radiating elements are regularly arranged and fed with a constant excitation condition, and each radiating element has a phase shifter (see FIG. (Not shown) is connected, and the main beam can be scanned at an arbitrary angle according to the set phase. An area switching unit for controlling the phase amount of each phase shifter is provided, and the area switching unit switches the phase amount so that the detection area for the external object is switched according to the operation mode set by the mode setting unit 5. Control. Specifically, as shown in FIG. 4A, in the rear-end collision detection mode, as shown in FIG. 4B, the detection area is widened so that both side directions with the possibility of rear-end collision can be detected. In the parking assistance mode, control is performed so that the detection area is narrowed down to detect an obstacle immediately behind the vehicle. Further, in the parking assist mode, the main beam may be controlled to scan in the backward direction of the vehicle in accordance with the steering operation amount by the rudder angle detection means 6d. The scanning direction of the main beam is not limited to the horizontal direction, and may be switched in the vertical direction. For example, in the case of parking assistance, the main beam may be controlled to be narrowed down to the rear of the vehicle.

  The operation of the vehicle periphery monitoring device described above will be described below based on the flowchart shown in FIG. When the ignition key is turned on and the engine is started, the mode setting means 5 determines which current operation mode is set (initially set to the rear-end collision detection mode) (S1), and detects rear-end collision. When the mode is set, the vehicle state data detected by the vehicle information detection means 6 is referred to (S2), and when the parking support mode is set, the process proceeds to step S16.

  When the rear-end collision detection mode is set, when the vehicle speed detection means 6b and the steering angle detection means 6d or the shift position detection means 6c detect that the vehicle is in a parking vehicle operating state, the attitude detection means 6a When the vehicle speed detecting means 6b or the shift position detecting means 6c detects that the vehicle is in the parking maneuvering state, the process proceeds to step S12 to switch the setting to the parking assist mode. Otherwise, that is, in the driving maneuvering state. When it is detected that there is, it is determined whether or not a manual switching operation has been performed on the touch panel of the monitor 9 by the driver (S3), and when it is determined that the operation has been performed, the process proceeds to step S12 to switch the setting to the parking assistance mode. If not, determine whether to perform computer timer interrupt processing set every few seconds S4).

  When the timer interrupt process is not necessary (S4), the rear-end collision detection mode is maintained, and the fact that the mode is set is displayed on the monitor 9 (S5), and the rear-end collision detection unit 20 outputs the output signal from the radar unit 4 to the output signal. Based on this, the risk of rear-end collision is predicted. When the danger of a rear-end collision is predicted (S6), the rear-end collision detection means 20 displays a rear-end collision warning message on the monitor 9 "A rear vehicle is approaching. Be careful" (S7). A voice message is output from the speaker 8 (S8), and active headrest control is started in response to the rear-end collision (S9).

  When the timer interrupt process is required in step S4, the radar means 4 is temporarily switched to the parking support mode and the parking support means 10 is operated (S10). The parking support means 10 is based on the output signal from the radar means 4 It is determined whether there is an obstacle within a predetermined range behind, and when it is predicted that a collision will occur when the vehicle moves backward (S11), a signal to that effect is output to the mode setting means 5. The mode setting means 5 receives the signal and switches the operation mode to the parking assistance mode to maintain the modes of the radar means 4 and the parking assistance means 10 (S12), and a voice message indicating that the mode has been switched to the parking assistance mode. Is output (S13), and the fact that the parking support mode is set is displayed on the monitor 9 (S14). When the parking support means 10 receives a signal indicating that there is no risk of collision, the mode setting means 5 returns the radar means 4 to the rear-end collision detection mode (S15).

  When it is determined in step S1 that the parking support mode is set, the vehicle state data is referred to in step S16. When the vehicle state data indicates the driving maneuvering state, the process proceeds to step S24 to switch the setting to the rear-end collision detection mode. Otherwise, that is, when it is detected that the vehicle is in the parking maneuvering state, the driver touches the monitor 9 In step S17, it is determined whether or not the manual switching operation has been performed. When it is determined that the manual switching operation has been performed, the process proceeds to step S24 to switch the setting to the rear-end collision detection mode. Is determined whether it is necessary (S18).

  When the timer interruption process is not necessary (S18), the parking support mode is maintained and the fact that the mode is set is displayed on the monitor 9 (S19). The parking support means 10 performs guidance for collision assistance to the monitor 9 while predicting the danger of collision based on the output signal from the radar means 4, that is, based on the relative relationship display information generated by the parking support display processing means. In addition to displaying the positional relationship between the vehicle in a backward posture and the obstacle (S20), a voice message such as “Please move backward as it is” or “Please operate the handle to the right” is displayed on the speaker by the parking assistance voice output means. 8 (S21).

  When timer interrupt processing is required in step S18, the radar means 4 is temporarily switched to the collision detection mode and the collision detection means 20 is operated (S22). The collision detection means 20 is based on the output signal from the radar means 4 and the vehicle. It is determined whether or not there is a vehicle that is abnormally approaching from within a predetermined range behind, and when it is predicted that there is a risk of a rear-end collision (S23), a signal to that effect is output to the mode setting means 5. The mode setting means 5 receives the signal and switches the operation mode to the rear-end collision detection mode to maintain the modes of the radar means 4 and the parking support means 10 (S24), and a voice message indicating that the mode has been switched to the rear-end collision detection mode. Is output (S25) and the fact that the rear-end collision detection mode is set is displayed on the monitor 9 (S26). When the rear collision detection means 20 receives a signal indicating that there is no risk of rear collision, the mode setting means 5 returns the radar means 4 to the parking support mode (S27). Such an operation is repeated at intervals of several milliseconds to several tens of milliseconds.

  Hereinafter, another embodiment of the present invention will be described. In the above-described embodiment, the case where the radar means adopting the spread spectrum method is used has been described. However, the radar means is not limited to such a method, and the CW radar or continuous wave transmitting a continuous wave signal is used. Other types of radar means such as an FMCW radar subjected to frequency modulation may be adopted.

  When the CW radar is employed, the received signal is mixed with the reference signal and converted to an intermediate frequency shifted by the frequency due to the Doppler shift, and input to the Doppler calculation means to detect the acceleration or velocity of the external object. When the Doppler calculation means is configured by hardware, a comb filter in which narrow band filters are arranged in a comb shape is used. At this time, since the acceleration level to be detected is different between the parking assistance mode and the rear-end collision detection mode, it is preferable that the frequency characteristics of the comb filter for performing frequency analysis are switched according to the operation mode. Further, when the Doppler calculation means is configured by software, frequency analysis is performed by FFT calculation. However, since the speed level to be detected differs between the parking support mode and the rear-end collision detection mode as described above, it is necessary depending on the operation mode. Processing speed can be improved by performing arithmetic processing only in a specific frequency region. In other words, it can be realized by providing the signal processing means with band switching means for switching the band for performing frequency analysis according to the set operation mode.

  When FMCW radar is used, there is little need to detect acceleration in the parking assist mode, so in this mode unnecessary calculation load is provided by providing the signal processing means with calculation process selection means for processing to omit acceleration calculation. Can be eliminated.

  In the above-described embodiment, an array antenna using a main beam scanned by a phase shifter has been described. However, when such an array antenna is used to simultaneously track multiple targets, reflections detected by a pair of antennas are detected. When the phase comparison monopulse method that obtains angle measurement information based on the phase difference of the waves is used, the detection angle range changes by changing the combination of the pair of antennas, and the parking assistance mode and the rear-end collision are used. You may comprise so that a detection range may be switched by changing the combination of an antenna in detection mode. In this case as well, the detection area is expanded so that it can detect both side directions that may cause a rear-end collision in the rear-end collision detection mode, and the detection area is set to detect an obstacle immediately behind the vehicle in the parking assistance mode. Switch control to narrow down.

  In the above-described embodiment, the detection range is switched using the array antenna. However, the detection range may be switched using a mechanical scanning antenna.

  The various embodiments described above can be combined as appropriate within a range where the effects of the present invention are achieved.

  The plurality of embodiments described above are merely examples of the present invention, and it is needless to say that the specific configuration of each block can be appropriately changed and designed within the scope of the effects of the present invention. It is also possible to appropriately combine the forms.

  As described above, according to the vehicle periphery monitoring device of the present invention, the radar means can be used for both parking assistance and rear-end collision detection, and it is not necessary to provide a separate monitoring device, so that the cost of parts can be reduced. Furthermore, the necessary output signal can be appropriately acquired from the radar means under various circumstances without the driver being aware of it.

Block diagram of vehicle periphery monitoring device Partial explanatory diagram of signal processing of spread spectrum radar means Flow chart explaining operation of vehicle periphery monitoring device Explanatory drawing when the detection range of the external object by the radar means is changed in the rear-end collision detection mode and the parking assistance mode

Explanation of symbols

1: transmission means 2: reception means 3: signal processing means 3a: synchronization processing means 3b: Doppler calculation means 3c: correlation calculation means 3d: correlation calculation switching means 4: radar means 5: mode setting means 10: parking support means 20: Rear-end collision detection means

Claims (8)

A vehicle periphery monitoring device comprising radar means for detecting an external object based on a reflected wave of a detection wave transmitted toward the outside of the vehicle,
A mode setting means for switching and setting the operation mode to any one of a parking assistance mode for operating the radar means as a support monitor at the time of parking and a rear-end collision detection monitor for operating as a rear-end collision at the time of traveling,
The mode setting means is a vehicle periphery monitoring device that sets the radar means to either a parking assistance mode or a rear-end collision detection mode based on vehicle state data.   The vehicle periphery monitoring device according to claim 1, wherein the vehicle state data is driving posture data detected by posture detecting means for detecting a driving posture of a driver.   2. The vehicle periphery monitoring device according to claim 1, wherein the vehicle state data is vehicle speed data detected by a vehicle speed sensor and shift position data detected by a shift position detecting means.   The vehicle periphery monitoring device according to claim 1, wherein the vehicle state data is steering angle data detected by a steering angle sensor.   5. The radar unit according to claim 1, wherein the radar unit is a CW radar or an FMCW radar, and the signal processing unit includes a band switching unit that switches a band for performing frequency analysis according to a set operation mode. Vehicle periphery monitoring device.   The vehicle periphery according to any one of claims 1 to 4, wherein the radar means is a spread spectrum radar and includes correlation calculation switching means for switching a sliding correlation calculation for an external object in accordance with a set operation mode. Monitoring device.   The vehicle periphery monitoring device according to any one of claims 1 to 4, wherein the radar means includes area switching means for switching a detection area for an external object in accordance with a set operation mode.   Priority mode setting means for preferentially setting the operation mode based on an output signal from the radar means when temporarily switching to the other operation mode during any one of the operation modes set by the mode setting means is provided. The vehicle periphery monitoring device according to claim 1.

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